Asphaltic products



Patented Sept. 27, 1966 3,275,586 ASPHALTIC PRQDUCTS Robert G. Wurstner, Richmond Heights, and Richard W.

Jahnlre, Mentor-on-the-Lalce, Ohio, assignors to The Lubrizol Corporation, Wiclrliffe, Ohio, a corporation of Ohio No Drawing. Filed Oct. 15, 1962, Ser. No. 230,728

4 Claims. (Cl. 260-285) This application is a continuation-in-part of application Serial No. 857,251, filed December 4, 1959, now U.S. Patent 3,093,610.

This invention relates as indicated to improved asphaltic products. More particularly it relates to a process for the preparation of asphaltic materials by a novel method whereby the penetration value of a petroleum residuum is reduced.

In the ordinary methods of refining petroleum a large fraction is obtained as the residue from distillation of certain crude oils. This fraction generally is referred to as the residuum, or as it has also come to be known, an asphalt flux. This latter terminology indicates the principal eifectiveness of this fraction as a starting material in the preparation of asphalt. This petroleum residuum or asphalt flux is a dark, very viscous fluid. It is susceptible to further distillation, but ordinarily the distillation of the crude oil is halted while some volatile material yet remains so as to minimize the thermal decomposition of this residue. Further distillation of this residue, while resulting in appreciable decomposition, results also in the formation of a type of asphalt and, except for the above noted thermal decomposition, asphalt could Well be produced simply by a continuation of the distillation. The decomposition results not only in the loss of a substantial proportion of material, but also in the formation of large quantities of coke, and the presence of such coke in the product is a serious disadvantage with respect to its use as an asphaltic material.

The principal production of asphalt, therefore, depends upon interrupting this distillation before the onset of substantial decomposition of the residuum and then treating this residuum, or asphalt flux, with steam and/or air. Such treatment minimizes losses by decomposition and results in a satisfactory asphaltic product. The steam treatment is a steam distillation which allows the further removal of volatile components at a reduced temperature. The step of treating with air consists merely in blowing air through the residuum at an elevated temperature, say, about 400 F. In some instances steam treatment or air treatment is employed alone, whereas in other instances both treatments are used. When the latter procedure is followed, the air-treatment generally follows the steam treatment. The step of treating a petroleum residuum with steam and/ or air appears to be effective as indicated above because it produces a chemical change in the petroleum residuum. Such change appears furthermore to be oxidative, and this affords a logical explanation of the physical transformations which are noted. As noted before, an advantage inherent in this known manner of preparing asphalt is the reduced temperature of the distillation which in turn minimizes loss by decomposition. There is, however, a lesser, though still significant loss which results from the steam treatment and/ or air treatment. As the steam and air are blown through the residuum, a significant volume of material is lost by entrainment in the escaping gases.

The most significant change which is effected by the above processes, viz., steam treatment and/or air treatment, as well as by the process of this invention, is a substantial reduction in the penetration value of the material. This penetration value, which measures the consistency of bituminous material, is expressed as the distance that a standard needle penetrates vertically into a sample of the material under known conditions of loading, time, and temperature. These conditions are grams, 5 seconds, and 25 C. (77 (R), respectively, and the units of penetration are expressed in hundredths of a centimeter. This penetration value is determined according to the procedure of ASTM Test -52, Standard Method of Test for Penetration of Bituminous Materials.

Another effect produced by the process of this invention is an increase in the resistance of the material to abrasion. This property is measured in terms of the weight loss of a patty weighing about 90 grams, comprising 98% sand and 2% of the asphalt sample, when that patty is subjected to the abrasive action of 500 grams of falling steel shot. The test is carried out by allowing the steel shot (IO- l4 mesh) to fall from the height of one meter onto the sand-asphalt patty as it is rotated at 360 rpm. The loss in weight of the patty as a consequence of this abrasive action is an indication of the resistance of the asphalt sample to abrasion. The abrasion loss generally is expressed in terms of grams per 1000 grams of steel shot. In a more severe version of this abrasion test, the asphalt-sand test patty is weathered in an infra-red oven at \F. for 90 0' hours and then subjected to the abrasion test set forth above. The asphaltic products of this invention show lower abrasion loss both initially and after 900 hours of weathering than asphaltic products produced from asphalt flux by conventional methods.

The asphaltic product which results from the process of this invention is characterized also by an improved compressive strength, i.e., it can withstand considerable mechanical pressure. This property is measured by subjecting a 2" x 2" cylindrically-shaped sand-asphalt mixture to a weight load applied to the curved peripheral surface normal to the axis of the sand-asphalt sample. The sample is prepared by mixing 100 parts of sand with 6 parts of asphalt and forming the mixture into the shape of a cylinder 2 inches long and 2 inches in diameter. The load applied is increased gradually until the cylindrical sample will support no further load. The load is expressed in pounds.

It is, accordingly, an object of this invention to provide an improved process for the preparation of asphaltic compositions.

Another object is to provide improved asphaltic compositions which are characterized 'by low abrasion loss and high compressive strength.

Yet another object is the provision of a process for the production of asphaltic compositions in better yields than have heretofore been obtained.

A still further object is to reduce the penetration value of a petroleum residuum by means of a convenient and economical process.

In accordance with the present invention, these and other objects of the invention are achieved by means 01 a process which comprises preparing a mixture of:

(A) 100 parts of a petroleum residuum,

(B) from about 2 to about 10 parts, preferably from about 3.5 to about 7.5 parts of a lower olefin polymer having an average molecular weight above about 1000, and

(C) from about 1 to about 6 parts, preferably from about 1.5 to about 3 parts of a compound selected from the group consisting of sulfur halides, phosphorus halides, phosphorus oxides, phosphorus sulfides, and phosphorus oxysulfides,

and heating said mixture to a temperature within the range from about 25 C. to about 200250 -C., preferably from about 100' C. to about 200 C.

The product which results from this process is characterized by a reduced penetration value as measured by the ASTM Test D-52, by .an improved resistance to abrasion, and by an increased compressive strength. These latter properties are especially important with respect to the use of asphalt in the preparation of road surfaces. It is apparent that the use of asphalt for such purposes requires excellent resistance to abrasion as well as a high order of resistance to direct pressure. Thus, the asphaltic compositions of this invention find their principal utility in the preparation of road surfaces. They are also useful in the preparation of built-up asphalt roofs, asphalt paints, asphalt-asbestos insulating compositions, asphalt shingles, and other well-known asphaltic products.

REAGENT A This reagent, the petroleum residuum or asphalt flux, may vary considerably depending upon the particular crude oil used, especially upon the geographic origin of the crude oil used. Thus some crude stocks will yield much larger proportions of residuum than others, and the variation in chemical composition of such residue likewise is considerable. The chemical identity of these residua, however, is not important with respect to the success of the process of this invention and it is unnecessary to become concerned about the differences in such chemical identities. These residua are best defined in terms of their penetration values and as a practical matter they are characterized by a penetration value of at least about 150 and preferably within the range of from about 180 to about 300. Such limits define the range of commercially available petroleum residua adapted for use in this process.

REAGENT B The lower olefin polymer useful as this reagent is a homopolymer or copolymer of a lower olefin of 2 to 6 carbon atoms such as ethylene, propylene, the various butylenes such as butene-l, butene-2, or isobutylene, the various amylenes such as pentene-l, pentene-2, 4-methylbutene-l, etc., hexene, butadiene-1,3, pentadiene-1,4, hexatriene-l,3,5, and the like. For use in the process of this invention, the polmer should have an average molecular weight above about 1000, with a preference for polymers having a molecular weight within the range from about 10,000 to about 200,000. The higher molecular weight polymers appear to be especially effective in achieving the stated objects of the invention, i.e., the use of a high molecular weight polymer is effective to reduce the penetration value of a petroleum residuum to a greater extent than can be accomplished by the use of a lower molecular weight polymer. The same relationship appears to exist between the molecular weight of the polymeric olefin and its influence upon the change in resistance to abrasion of the treated residuum. An especially effective molecular weight appears to be about 50,000- 65,000.

In most instances the polymer employed will be subtantially aliphatic, that is, it will contain not less than about 75 percent of aliphatic units within its structure. Thus, the polymer may be and most often is a wholly aliphatic polymer such as a homopolymer of one of the above-described aliphatic lower olefins or a copolymer of two or more such olefins. In some instances it may be, however, a polymer containing up to 25 percent of aromatic or heterocyclic units, which polymer is derived from the copolymerization of, say, 75 to 99 parts of an aliphatic lower olefin such as ethylene, propylene, isobutylene, etc., with from 25 to 1 part of an aromaticor heterocyclic-substituted olefin such as styrene, parachlorostyrene, alpha-methyl-styrene, N-vinyl pyridine, N- vinyl pyrrolidone, N-vinyl oxazolidone, unsymmetrical diphenyl ethylene, etc. Specific examples of polymers useful in the process of this invention are polyethylene, polypropylene, a copolymer of 60 parts of ethylene and 40 parts of propylene, polyisobutylene, a copolymer of 96 parts of isobutylene and 4 parts of butadiene, a copolymer of parts of isobutylene and 5 parts of styrene, a copolymer of 98 parts of isobutylene and 2 parts of para-chlorostyrene, a copolymer of 94 parts of isobutylene and 6 parts of isoprene, a copolymer of 85 parts of isobutylene and 15 parts of vinyl pyridine, and others. The preparation of such polymers is well known and need not be described here.

The preferred polymers are the homopolymers of isobutylene. Such preference is based not only on the commercial availability of these polymers, but also on their particular efficacy. The high molecular weight polyisobutylenes have been found to be most useful in the process. Thus, polyisobutylenes having a molecular weight of 40,000, 50,000 or 63,000 have given good results, i.e., the asphaltic products which result from their use in the process are very much improved in all of the abovementioned properties.

REAGENT C As previously noted, this reagent is a compound selected from the group consisting of sulfur halides, phosphorus halides, phosphorus oxides, phosphorus sulfides, and phosphorus oxysulfides. Specific examples of this reagent include sulfur monochloride, sulfur monobromide, sulfur hexaiodide, sulfur tetrachloride, sulfuryl chloride, thionyl chloride, sulfur oxytetrachloride, phosphorus trichloride, phosphorus tribromide, phosphorus pentachloride, phosphorus bromotetrachloride, phosphorus trriodide, phosphorus oxychloride, phosphorus thiochloride, phosphorus trichloride plus sulfur (found to approximate phosphorus thiochloride in its effect), phosphorus trifluoride, phosphorus oxybromide, phos phorus trioxide, phosphorus tetraoxide, phosphorus pentoxide, phosphorus sesquisulfide, phosphorus pentasulfide, phosphorus heptasulfide, phosphorus hexaoxytetrasulfide, etc. Of the various sulfur halides and phosphorus halides which can be employed, the sulfur chlorides and phosphorus chlorides are preferred by reason of their low cost and commercial availability. Likewise, of the various phosphorus oxides and phosphorus sulfides, phosphorus pentoxide and phosphorus pentasulfide are preferred.

In lieu of a single reagent C, mixtures of two or more of such reagents may be employed, e.g., equal parts by weight sulfur monochloride and sulfur dichloride, 3 parts of sulfur monochloride and 1 part of phosphorus trichloride, and similar mixtures.

The relative proportions of reagents A, B, and C in the process of this invention are critical. That is, the use of amounts of these reagents outside the stated ranges re sults in an asphaltic product of inferior properties. The optimum ratio of the three reagents appears to be about 100:5 :2 or 3, respectively. When less than the stated minimum amounts of reagents B and/ or C are employed per 100 parts of reagent A, the asphaltic product which results is not significantly different from the starting petroleum residuum. On the other hand, when more than the stated maximum amount of reagent C is employed per 100 parts of reagent A, a hard, brittle, cokelike material results. This latter material is of little or no value with respect to the usual applications of asphalt.

Ordinarily the process of this invention is carried out by mixing reagents A and B, the residuum and olefin polymer, heating such mixture to effect an intimate blend of the two reagents, allowing the mass to cool to about 100 C., and then adding reagent C portionwise. The resulting reaction is exothermic and proceeds as fast as reagent C is added, provided the reagents are mixed well. The process of the invention is generally carried out within the temperature range from about 50 C. to about 250 C., more often from about 100 C. to about 200 C.

The following examples are presented to illustrate specific modes of carrying out the process of the present invention. They are given for purposes of illustration only and are not to be construed as limiting the scope of the invention, except as the latter is defined by the appended claims. Unless otherwise stated, all parts and percentages are by weight.

Example 1 A mixture of 960 grams of an asphalt flux having a penetration value of 250 and 48 grams of a polyisobutylene having an average molecular weight of about 50,000 is prepared and heated with stirring to 210 C. When this temperature is reached, the mixture is allowed to cool to 100 C., whereupon 19.2 grams of sulfur monochloride is added portionwise, each portion being added only when the preceding portion has been consumed by an exothermic reaction. The addition of the sulfur monochloride is completed within about minutes. The product mixture is then heated to 225 C. for 0.5 hour and allowed to cool. The asphaltic product obtained shows a penetration value of 87, a compressive strength of 21 pounds, and the absence of surface skin when subjected to a thin film thermal stability test. This latter test consists of heating a thin film of a sample at 325 F. for 5 hours. The sample is prepared by placing 50 grams of the asphalt in a flat bottomed aluminum dish having a diameter of 5.5 inches. At the conclusion of the heating period, the presence or absence of a skin on the surface is noted. The absence of such a skin is an indication that the sample possesses good thermal stability.

Example 2 A mixture of 1,002 grams of an asphalt flux having a penetration value of 250 and 50 grams of a polyisobutylene having an average molecular weight of 63,000 is prepared and heated with stirring to 200 C. The mixture is then allowed to cool to 100 C. and 30 grams of phosphorus trichloride is added portionwise over a period of 0.5 hour, allowing the exothermic reaction which takes place upon the addition of a portion of the phosphorus trichloride to cease before another portion is added. Thereafter, the whole is heated at 200 C. for 0.5 hour and then vacuum stripped at 10 mm. Hg for 0.25 hour to remove any traces of HCl gas. The asphaltic product obtained shows a penetration value of 90.

Example 3 A mixture of 960 grams of an asphalt flux having a penetration value of 250 and 48 grams of a polyisobutylone having an average molecular weight of 63,000 is prepared and heated with stirring to 200 C. Thereupon, the mixture is allowed to cool to 100 C. and 29 grams of thionyl chloride is added portionwise over a. period of 0.5 hour. The whole is heated at 200 C. for 25 minutes and then vacuum stripped at 100 mm. Hg for 0.25 hour to remove any traces of HCl gas. The asphaltic product obtained shows a penetration value of 85.

Example 4 1,001 grams of an asphalt flux having a penetration value of 250 and 50 grams of a polyisobutylene having an average molecular weight of 63,000 are mixed and heated with stirring to 200 C. Thereupon, the whole is allowed to cool to 100 C. and 30 grams of sulfur dichloride is a-ded portionwise over a period of 0.5 hour. The reaction mass is then heated at 200 C. for 25 minutes and vacuum stripped at 10 mm. Hg for about 20 minutes to remove any traces of HCl gas. The asphaltic product obtained shows a penetration value of 69.

Example 5 A mixture of 999 grams of an asphalt flux having a penetration value of 250 grams of a polyisobutylene having an average molecular weight of 63,000 is prepared and heated with stirring to 200 C. Thereupon, the mixture is allowed to cool to 100 C. and 30 grams of phos- 6 phorus thiochloride is added portionwise over a period of 0.5 hour. The whole is then heated at 200 C. for 0.5 hour and vacuum stripped at 10 mm. Hg for 0.25 hour to remove any traces of HCl gas. The asphaltic product obtained shows a penetration value of 65.

Example 6 A mixture of 999 grams of an asphalt flux having a penetration value of 250 and 50 grams of a polyisobutylene having an average molecular weight of 63,000 is prepared and heated with stirring to 200 C. Thereupon, the whole is allowed to cool to C. and 30 grams of phosphorus pentoxide is added portionwise over a period of 0.5 hour. The reaction mixture is then heated at 200 C. for 25 minutes and Vacuum stripped at 10 mm. Hg for 20 minutes to remove any hydrogen sulfide present. The asphaltic product obtained shows a penetration value 0 63.

Example 7 A mixture of 990 grams of an asphalt flux having a penetration value of 250 and 49 grams of a polyisobutylone having an average molecular weight of 63,000 is stirred and heated to 100 C. 10 grams of sulfur flowers is added and the whole is heated to 200 C. and allowed to cool to 100 C. Then 30 grams of phosphorus trichloride is added portionwise over a period of 0.5 hour and the whole is heated once more to 200 C. for 25 minutes. The contents of the reaction vessel are then vacuum stripped at 10 mm. Hg for 10 minutes to remove any traces of HCl gas. The asphaltic product obtained shows a penetration value of 48.

Example 8 A mixture of 1,001 grams of an asphalt flux having a penetration value of 250 and 51 grams of a polyisobutylene having an average molecular weight of 63,000 is prepared and heated with stirring to 200 C. Thereupon the whole is allowed to cool to 100 C. and 30 grams of phosphorus pentasulfide is added portionwise over a period of 6 hours at about 100 C. After all of the phosphorus pentasulfide has been added, the reaction mixture is heated to 200 C. and maintained at this temperature for 0.5 hour. The contents of the reaction vessel are then vacuum stripped at 10 mm. Hg for 20 minutes to remove any dissolved hydrogen sulfide. The asphaltic product obtained shows a penetration value of 46.

A number of asphaltic compositons of this invention were subjected to the abrasion test described earlier. It was observed that these asphaltic compositions were substantially more resistant to loss by abrasion than an asphalt produced by a conventional method from the identical asphalt flux employed as a starting material for the asphaltic compositions of this invention. The test results are shown in the following table.

TABLEAB RASION LOSS TEST Abrasion Loss Value Asphaltic Composition Used to Prepare the Test Patty After 900 hrs.

Initial exposure in infrared oven at F.

Product of Example 1 Product of Example 2 Product of Example 3 Product of Example 4--" Product of Example 7.. Product of Example 8 Control (conventional asphalt Control (special asphalt It should be noted that not only are the asphaltic compositions of this invention more resistant initially to loss by abrasion than a conventional asphalt but that such resistance suffers relatively little change after exposure of the test sample to infra-red weatheriing for 900 hours at 140 F. On the other hand the resistance of the conventional asphalt to loss by abrasion is seen to deteriorate substantially under these more rigorous test conditions. It should also be noted (cf. test data on special asphalt) that when the use of reagent B, the lower olefin polymer, is omitted incarrying out the process of this invention, the resulting asphaltic product is inferior to the products of this invention as regards resistance to loss by abrasion. In fact, such asphaltic product is even inferior to the conventional asphalt produced by an air-treatment process.

A particular advantage of the process of this invention is the fact that a larger yield of asphalt can be obtained from a given amount of asphalt flux or petroleum residuum than is available from conventional steam treatment and/ or air treatment processes. As indicated earlier a significant loss of mate-rial characterizes these latter processes. On the other hand, there is no loss whatsoever of asphalt flux in carrying out the process of this invention.

What is claimed is:

1. A process for making an improved asphaltic composition which comprises reacting at a temperature within the range of from about 50 C. to about 250 C., a mixture of:

(A) 100 parts of a petroleum residuum having a penetration value within the range of from about 150 to about 300,

(B) from about 2 to about parts of a lower olefin polymer obtained from an olefin having from 2 to about 6 carbon atoms, the polymer having a molecular weight of at least about 1000, and

(C) from about 1 to 6 parts of a phosphorus halide.

2. A process for making an improved asphaltic composition which comprises reacting at a temperature within the range of from about C. to about 200 C., a mixture of:

(A) 100 parts of a petroleum residuum having a penetration value within the range of from about 180 to about 300,

(B) from about 3.5 to about 7.5 parts of a polyisobutylene having a molecular Weight within the range of from about 10,000 to about 200,000, and

(C) from about 1.5 to about 3 parts of a phosphorus halide.

3. The process of claim 1 characterized further in that component (B) is a polyisobutylene having a molecular weight of about 50,000 to about 65,000.

4. The process of claim 1 characterized further in that component (C) is phosphorus trichloride.

References Cited by the Examiner UNITED STATES PATENTS 2,842,507 7/ 1958 Morris. 2,909,498 10/ 1959 Sayko. 3,010,928 11/1961 Odasz et a1. 260-28.5

FOREIGN PATENTS 602,582 5/ 1948 Great Britain.

OTHER REFERENCES Abraham, Asphalts and Allied Substances, vol. I, 5th edition, Van Nostrand, N.Y., pages 87 and 493, 1945, C. 6.

Rose, The Condensed Chemical Dictionary. Reinhold Publishing Corp., N.Y., 1962.

MORRIS LIEBMAN, Primary Examiner.

D. C. KOLASCH, B. A. AMERNICK,

Assistant Examiners. 

1. A PROCESS FOR MAKING AN IMPROVED ASPHALTIC COMPOSITION WHICH COMPRISES REACTING AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 50*C. TO ABOUT 250*C., A MIXTURE OF: (A) 100 PARTS OF A PETROLEUM RESIDUUM HAVING A PENETRATION VALUE WITHIN THE RANGE OF FROM ABOUT 150 TO ABOUT 300, (B) FROM ABOUT 2 TO ABOUT 10 PARTS OF LOWER OLEFIN POLYMER OBTAINED FROM AN OLEFIN HAVING FROM 2 TO ABOUT 6 CARBON ATOMS, THE POLYMER HAVING A MOLECULAR WEIGHT OF AT LEAST ABOUT 1000, AND (C) FROM ABOUT 1 TO 6 PARTS OF A PHOSPHORUS HALIDE. 